Merge pull request #1934 from benpeart/fscache-thread-safe-enable-gfw

fscache: make fscache_enable() thread safe

Author: dscho

.gitattributes

@@ -4,6 +4,7 @@
 *.perl eol=lf diff=perl
 *.pl eof=lf diff=perl
 *.pm eol=lf diff=perl
+*.png binary
 *.py eol=lf diff=python
 *.bat eol=crlf
 /Documentation/**/*.txt eol=lf

Makefile

@@ -706,6 +706,7 @@ X =
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 
 TEST_BUILTINS_OBJS += test-chmtime.o
+TEST_BUILTINS_OBJS += test-cmp.o
 TEST_BUILTINS_OBJS += test-config.o
 TEST_BUILTINS_OBJS += test-ctype.o
 TEST_BUILTINS_OBJS += test-date.o
@@ -721,6 +722,7 @@ TEST_BUILTINS_OBJS += test-genzeros.o
 TEST_BUILTINS_OBJS += test-hash.o
 TEST_BUILTINS_OBJS += test-hashmap.o
 TEST_BUILTINS_OBJS += test-hash-speed.o
+TEST_BUILTINS_OBJS += test-iconv.o
 TEST_BUILTINS_OBJS += test-index-version.o
 TEST_BUILTINS_OBJS += test-json-writer.o
 TEST_BUILTINS_OBJS += test-lazy-init-name-hash.o

compat/mingw.c

@@ -10,6 +10,8 @@
 #include "../config.h"
 #include "dir.h"
 #include "../attr.h"
+#include "../string-list.h"
+#include "win32/fscache.h"
 
 #define HCAST(type, handle) ((type)(intptr_t)handle)
 
@@ -1387,6 +1389,65 @@ static char *lookup_prog(const char *dir, int dirlen, const char *cmd,
 	return NULL;
 }
 
+static char *path_lookup(const char *cmd, int exe_only);
+
+static char *is_busybox_applet(const char *cmd)
+{
+	static struct string_list applets = STRING_LIST_INIT_DUP;
+	static char *busybox_path;
+	static int busybox_path_initialized;
+
+	/* Avoid infinite loop */
+	if (!strncasecmp(cmd, "busybox", 7) &&
+	    (!cmd[7] || !strcasecmp(cmd + 7, ".exe")))
+		return NULL;
+
+	if (!busybox_path_initialized) {
+		busybox_path = path_lookup("busybox.exe", 1);
+		busybox_path_initialized = 1;
+	}
+
+	/* Assume that sh is compiled in... */
+	if (!busybox_path || !strcasecmp(cmd, "sh"))
+		return xstrdup_or_null(busybox_path);
+
+	if (!applets.nr) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		struct strbuf buf = STRBUF_INIT;
+		char *p;
+
+		argv_array_pushl(&cp.args, busybox_path, "--help", NULL);
+
+		if (capture_command(&cp, &buf, 2048)) {
+			string_list_append(&applets, "");
+			return NULL;
+		}
+
+		/* parse output */
+		p = strstr(buf.buf, "Currently defined functions:\n");
+		if (!p) {
+			warning("Could not parse output of busybox --help");
+			string_list_append(&applets, "");
+			return NULL;
+		}
+		p = strchrnul(p, '\n');
+		for (;;) {
+			size_t len;
+
+			p += strspn(p, "\n\t ,");
+			len = strcspn(p, "\n\t ,");
+			if (!len)
+				break;
+			p[len] = '\0';
+			string_list_insert(&applets, p);
+			p = p + len + 1;
+		}
+	}
+
+	return string_list_has_string(&applets, cmd) ?
+		xstrdup(busybox_path) : NULL;
+}
+
 /*
  * Determines the absolute path of cmd using the split path in path.
  * If cmd contains a slash or backslash, no lookup is performed.
@@ -1415,6 +1476,9 @@ static char *path_lookup(const char *cmd, int exe_only)
 		path = sep + 1;
 	}
 
+	if (!prog && !isexe)
+		prog = is_busybox_applet(cmd);
+
 	return prog;
 }
 
@@ -1606,11 +1670,16 @@ static int is_msys2_sh(const char *cmd)
 }
 
 static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaenv,
-			      const char *dir,
-			      int prepend_cmd, int fhin, int fhout, int fherr)
+			      const char *dir, const char *prepend_cmd,
+			      int fhin, int fhout, int fherr)
 {
-	STARTUPINFOW si;
+	static int restrict_handle_inheritance = 1;
+	STARTUPINFOEXW si;
 	PROCESS_INFORMATION pi;
+	LPPROC_THREAD_ATTRIBUTE_LIST attr_list = NULL;
+	HANDLE stdhandles[3];
+	DWORD stdhandles_count = 0;
+	SIZE_T size;
 	struct strbuf args;
 	wchar_t wcmd[MAX_PATH], wdir[MAX_PATH], *wargs, *wenvblk = NULL;
 	unsigned flags = CREATE_UNICODE_ENVIRONMENT;
@@ -1647,11 +1716,23 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 		CloseHandle(cons);
 	}
 	memset(&si, 0, sizeof(si));
-	si.cb = sizeof(si);
-	si.dwFlags = STARTF_USESTDHANDLES;
-	si.hStdInput = winansi_get_osfhandle(fhin);
-	si.hStdOutput = winansi_get_osfhandle(fhout);
-	si.hStdError = winansi_get_osfhandle(fherr);
+	si.StartupInfo.cb = sizeof(si);
+	si.StartupInfo.hStdInput = winansi_get_osfhandle(fhin);
+	si.StartupInfo.hStdOutput = winansi_get_osfhandle(fhout);
+	si.StartupInfo.hStdError = winansi_get_osfhandle(fherr);
+
+	/* The list of handles cannot contain duplicates */
+	if (si.StartupInfo.hStdInput != INVALID_HANDLE_VALUE)
+		stdhandles[stdhandles_count++] = si.StartupInfo.hStdInput;
+	if (si.StartupInfo.hStdOutput != INVALID_HANDLE_VALUE &&
+	    si.StartupInfo.hStdOutput != si.StartupInfo.hStdInput)
+		stdhandles[stdhandles_count++] = si.StartupInfo.hStdOutput;
+	if (si.StartupInfo.hStdError != INVALID_HANDLE_VALUE &&
+	    si.StartupInfo.hStdError != si.StartupInfo.hStdInput &&
+	    si.StartupInfo.hStdError != si.StartupInfo.hStdOutput)
+		stdhandles[stdhandles_count++] = si.StartupInfo.hStdError;
+	if (stdhandles_count)
+		si.StartupInfo.dwFlags |= STARTF_USESTDHANDLES;
 
 	if (*argv && !strcmp(cmd, *argv))
 		wcmd[0] = L'\0';
@@ -1667,9 +1748,9 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 	/* concatenate argv, quoting args as we go */
 	strbuf_init(&args, 0);
 	if (prepend_cmd) {
-		char *quoted = (char *)quote_arg(cmd);
+		char *quoted = (char *)quote_arg(prepend_cmd);
 		strbuf_addstr(&args, quoted);
-		if (quoted != cmd)
+		if (quoted != prepend_cmd)
 			free(quoted);
 	}
 	for (; *argv; argv++) {
@@ -1713,16 +1794,97 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 	wenvblk = make_environment_block(deltaenv);
 
 	memset(&pi, 0, sizeof(pi));
-	ret = CreateProcessW(*wcmd ? wcmd : NULL, wargs, NULL, NULL, TRUE,
-		flags, wenvblk, dir ? wdir : NULL, &si, &pi);
+	if (restrict_handle_inheritance && stdhandles_count &&
+	    (InitializeProcThreadAttributeList(NULL, 1, 0, &size) ||
+	     GetLastError() == ERROR_INSUFFICIENT_BUFFER) &&
+	    (attr_list = (LPPROC_THREAD_ATTRIBUTE_LIST)
+			(HeapAlloc(GetProcessHeap(), 0, size))) &&
+	    InitializeProcThreadAttributeList(attr_list, 1, 0, &size) &&
+	    UpdateProcThreadAttribute(attr_list, 0,
+				      PROC_THREAD_ATTRIBUTE_HANDLE_LIST,
+				      stdhandles,
+				      stdhandles_count * sizeof(HANDLE),
+				      NULL, NULL)) {
+		si.lpAttributeList = attr_list;
+		flags |= EXTENDED_STARTUPINFO_PRESENT;
+	}
+
+	ret = CreateProcessW(*wcmd ? wcmd : NULL, wargs, NULL, NULL,
+			     stdhandles_count ? TRUE : FALSE,
+			     flags, wenvblk, dir ? wdir : NULL,
+			     &si.StartupInfo, &pi);
+
+	/*
+	 * On Windows 2008 R2, it seems that specifying certain types of handles
+	 * (such as FILE_TYPE_CHAR or FILE_TYPE_PIPE) will always produce an
+	 * error. Rather than playing finicky and fragile games, let's just try
+	 * to detect this situation and simply try again without restricting any
+	 * handle inheritance. This is still better than failing to create
+	 * processes.
+	 */
+	if (!ret && restrict_handle_inheritance && stdhandles_count) {
+		DWORD err = GetLastError();
+		struct strbuf buf = STRBUF_INIT;
+
+		if (err != ERROR_NO_SYSTEM_RESOURCES &&
+		    /*
+		     * On Windows 7 and earlier, handles on pipes and character
+		     * devices are inherited automatically, and cannot be
+		     * specified in the thread handle list. Rather than trying
+		     * to catch each and every corner case (and running the
+		     * chance of *still* forgetting a few), let's just fall
+		     * back to creating the process without trying to limit the
+		     * handle inheritance.
+		     */
+		    !(err == ERROR_INVALID_PARAMETER &&
+		      GetVersion() >> 16 < 9200) &&
+		    !getenv("SUPPRESS_HANDLE_INHERITANCE_WARNING")) {
+			DWORD fl = 0;
+			int i;
+
+			setenv("SUPPRESS_HANDLE_INHERITANCE_WARNING", "1", 1);
+
+			for (i = 0; i < stdhandles_count; i++) {
+				HANDLE h = stdhandles[i];
+				strbuf_addf(&buf, "handle #%d: %p (type %lx, "
+					    "handle info (%d) %lx\n", i, h,
+					    GetFileType(h),
+					    GetHandleInformation(h, &fl),
+					    fl);
+			}
+			strbuf_addstr(&buf, "\nThis is a bug; please report it "
+				      "at\nhttps://github.com/git-for-windows/"
+				      "git/issues/new\n\n"
+				      "To suppress this warning, please set "
+				      "the environment variable\n\n"
+				      "\tSUPPRESS_HANDLE_INHERITANCE_WARNING=1"
+				      "\n");
+		}
+		restrict_handle_inheritance = 0;
+		flags &= ~EXTENDED_STARTUPINFO_PRESENT;
+		ret = CreateProcessW(*wcmd ? wcmd : NULL, wargs, NULL, NULL,
+				     TRUE, flags, wenvblk, dir ? wdir : NULL,
+				     &si.StartupInfo, &pi);
+		if (ret && buf.len) {
+			errno = err_win_to_posix(GetLastError());
+			warning("failed to restrict file handles (%ld)\n\n%s",
+				err, buf.buf);
+		}
+		strbuf_release(&buf);
+	} else if (!ret)
+		errno = err_win_to_posix(GetLastError());
+
+	if (si.lpAttributeList)
+		DeleteProcThreadAttributeList(si.lpAttributeList);
+	if (attr_list)
+		HeapFree(GetProcessHeap(), 0, attr_list);
 
 	free(wenvblk);
 	free(wargs);
 
-	if (!ret) {
-		errno = ENOENT;
+	if (!ret)
 		return -1;
-	}
+
 	CloseHandle(pi.hThread);
 
 	/*
@@ -1746,7 +1908,8 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 	return (pid_t)pi.dwProcessId;
 }
 
-static pid_t mingw_spawnv(const char *cmd, const char **argv, int prepend_cmd)
+static pid_t mingw_spawnv(const char *cmd, const char **argv,
+			  const char *prepend_cmd)
 {
 	return mingw_spawnve_fd(cmd, argv, NULL, NULL, prepend_cmd, 0, 1, 2);
 }
@@ -1774,14 +1937,14 @@ pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **deltaenv,
 				pid = -1;
 			}
 			else {
-				pid = mingw_spawnve_fd(iprog, argv, deltaenv, dir, 1,
+				pid = mingw_spawnve_fd(iprog, argv, deltaenv, dir, interpr,
 						       fhin, fhout, fherr);
 				free(iprog);
 			}
 			argv[0] = argv0;
 		}
 		else
-			pid = mingw_spawnve_fd(prog, argv, deltaenv, dir, 0,
+			pid = mingw_spawnve_fd(prog, argv, deltaenv, dir, NULL,
 					       fhin, fhout, fherr);
 		free(prog);
 	}
@@ -1809,7 +1972,7 @@ static int try_shell_exec(const char *cmd, char *const *argv)
 		argv2[0] = (char *)cmd;	/* full path to the script file */
 		memcpy(&argv2[1], &argv[1], sizeof(*argv) * argc);
 		exec_id = trace2_exec(prog, argv2);
-		pid = mingw_spawnv(prog, argv2, 1);
+		pid = mingw_spawnv(prog, argv2, interpr);
 		if (pid >= 0) {
 			int status;
 			if (waitpid(pid, &status, 0) < 0)
@@ -1833,7 +1996,7 @@ int mingw_execv(const char *cmd, char *const *argv)
 		int exec_id;
 
 		exec_id = trace2_exec(cmd, (const char **)argv);
-		pid = mingw_spawnv(cmd, (const char **)argv, 0);
+		pid = mingw_spawnv(cmd, (const char **)argv, NULL);
 		if (pid < 0) {
 			trace2_exec_result(exec_id, -1);
 			return -1;
@@ -3013,6 +3176,9 @@ int wmain(int argc, const wchar_t **wargv)
 	InitializeCriticalSection(&pinfo_cs);
 	InitializeCriticalSection(&phantom_symlinks_cs);
 
+	/* initialize critical section for fscache */
+	InitializeCriticalSection(&fscache_cs);
+
 	/* set up default file mode and file modes for stdin/out/err */
 	_fmode = _O_BINARY;
 	_setmode(_fileno(stdin), _O_BINARY);